在超音速流場內之液態噴流具有複雜之物理現象，因為，其牽涉到噴霧在超音速紊流場中之霧化與蒸發，以及震波與邊界層之交互作用等複雜之物理問題。因此，對霧化機制之了解有助於分析探討液態燃料在超音速燃燒衝壓引擎之霧化及燃燒現象。目前液態燃料的使用，為不可避免之趨勢，但液態燃料需考慮燃料霧化程度、蒸發過程以及燃燒延遲等現象，因此增添流場之複雜性。然而實驗在觀察如此之迅速的物理現象上較為困難，為此需建立一合理之噴霧數值模型，模擬複雜流場之物理現象，因此本文將使用CFD 計算流體力學，ANSYS FLUENT 軟體，進行液態水注入超音速流場之數值模擬計算，紊流模式採用SST K-ω，霧化模式則採用Kelvin-Helmholtz/Rayleigh-Taylor(K-H/R-T)破碎模式。本研究針對KH/R-T破碎參數做分析，探討不同參數對超音速流場之噴霧結構的影響，發現CL參數對K-H model 和R-T model 之作用區域以及作用程度有非常大的關係，且粒徑參數比時間參數更能主導穿透高度之趨勢。再者，針對液態碳氫燃料注入超音速流場之模擬分析，首先進行不同噴注速度之分析，發現在比較噴注速度為78m/s 及85m/s 時，噴注速度越大弓形震波產生之壓力越大，且角度也越大，越容易注入流場內。接著進行不同噴注角度之分析，發現在比較噴注角度30 度、45 度及垂直上噴時，噴注45 度液滴的碎裂霧化效果最好。之後進行不同燃料溫度之分析，發現在比較攝氏30 度、攝氏100 度及攝氏130 度之燃料溫度後，攝氏130 度之煤油蒸發效果最好，蒸發量也最多。

In the present study, the CFD software ANSYS-FLUENT was employed to conduct a numerical simulation of water and liquid-hydrocarbon fuel injection in a supersonic flow,
respectively. Both the SST k-ω turbulence model and the K-H/R-T breakup model were adopted for this analysis. Through analyzing the different parameters of the K-H/R-T model affecting the water-jet breakup and atomization, it was found that the effective area of K-H model extended as the CL parameter, which controls the length of liquid core region, increased. The penetration height was much more dominated by particle size parameters such as B0 and CRT than it was by time parameters like B1 and Ctau. When comparing the injection speed at 75m/s with that at 80m/s for liquid-hydrocarbon fuel injection in a supersonic flow, it could be seen that a faster speed may increase the pressure behind the bow shock and angle of the bow shock wave. Furthermore, atomization at a forward angle of 45-degree relative to vertical direction turns out to be the most effective method by which to compare a forward angle of 30-degree and a vertical injection. When analyzing the evaporation effects of the fuel temperature at 30℃, 100℃and 130℃ separately, it was found that evaporation worked best at a temperature of 130℃.

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